For a pull-only, static registry, there only a couple of headers that need to be optional (that are presently required. * X-Docker-Registry-Version * X-Docker-Size * X-Docker-Endpoints Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts) Upstream-commit: 2a2c694758d6a48125cc9adf446f2054b52db201 Component: engine